Commercial wireless communication services such as cellular phone services and wireless data services are available on an increasing number of radio frequency (RF) bands. In the United States, for example, cellular and data services are currently available on the cellular band or Advanced Mobile Phone System (AMPS) band and the Personal Communication Service (PCS) band. In addition, the Advanced Wireless Services (AWS) band has also recently become available for providing commercial wireless services.
To more fully utilize multiple RF bands and enhance the value of a portable wireless device, it is desirable to have a portable, multi-band wireless device that is capable of transmitting and receiving signals on different RF bands. A multi-band wireless device represents an integration of various wireless technologies into a single portable device so that the device can use different RF bands. A dual-band cellular phone capable of using the analog AMPS band and digital PCS band is a common example of a multi-band portable device. As more commercial RF bands become available for portable devices, it is desirable to have portable devices that can take advantage of these additional bands. Accommodating these additional RF bands in a portable wireless device requires innovative approaches to antenna and RF circuitry design in the device.
In addition, in some multi-band wireless devices, it is also desirable to integrate a Global Positioning System (GPS) function. A hand-held GPS device provides positional information, related to the location of the GPS device, by receiving and processing GPS band signals from the GPS satellite system. Although such positional information can be quite useful, it is not always convenient to carry a separate GPS device, especially if a user also carries around one or more other portable wireless devices, such as a laptop, cellular phone, Personal Digital Assistant (PDA), or other similar device. It is therefore desirable that the GPS positioning function be integrated within one of these other portable devices.
Unfortunately, known approaches for integrating certain wireless and GPS technologies into a portable, multi-band device have proven to be relatively difficult and costly in terms of added components, power consumption, and physical size. Much of difficulty arises in the design of the antennas and RF circuitry in the portable device. Some conventional design approaches to integrated multi-band devices involve putting multiple antennas into the portable device to handle the different RF bands and GPS band. However, multiple antennas add extra cost and design complexity to the device. Thus, there is a need for a better solution to integrating multiple RF bands and GPS functionality into portable wireless devices.